腹癒せ

はらいせ [haraise] – Literally, “soothing the stomach”. This expression refers to taking your anger out on something. In a strict definition, it means to direct your anger toward something different or unrelated to the source of the anger, but it is also frequently used to describe actions taken in retaliation or to spite someone.

Note: 癒 is often left just as the hiragana い for difficulty reasons.

ふられた腹いせに噂を流すTo spread rumors (about someone) in retaliation for being dumped.